Gaseous discharge lamp



May 4, 1943.

A. KOB ER ETAL I GASEOUS DISCHARGE LAMP Filed ma 9, 1941 3 Sheets-Sheet l I 'TILO niese.

May 4, 1943. P. A. KOBER :ET AL 2,318,032

GASEOUS DISCHARGE LAMP Filed May 9, 1941 s Sheet-Sheet '2 Paul Kobe? Thomas M Cortese BMW- y 1943- FLA. KOBEYR ETAL 2,318,082

GASEOUS DISCHARGE LAMP Filed May 9, 1941 3 Sheets-Sheet 5 Patented May 4, 1943- UNITED STATES PATENTAOFFICE 7 2,318,082 1 GASEOUS nrscnanca LAMI- Paul Alexander Kober, Orange, and Thomas M.

Y Cortese, East Orange, N. J.

ASppIication May 9, 19 Serial 'No. 392,782

13 Claims. (Cld176-1 24) The present inventionrelates to gaseous discharge tubes and more tubes.

An important object of the invention is to provide a tube of the above-mentioned character which may be operated by a simplified circuit.

A further object of the invention is to provide a tube of the above-mentioned character which is positive and instantaneous in starting.

A further object of the invention is to provide a tube of the above-mentioned character which will have efiiciencies equal to the present commercial low voltage fluorescent, tubes.

A further object of the invention is to provide a tube of the above-mentioned character so constructed that failure of the tube to lightup, due to the drop in line voltage, or increased voltage requirements of the tube which may be caused by the electron emission coating failure, is eliminated. v

A further object of the invention-is to provide tubes of suitable-commercial lengths which will particularly to fluorescent operate on alow voltage below the GOO-volt limit,

whereby thepresent high voltage type restrictions for interior installations, as regulated by under-v writers, municipal and will be avoided.

a A further object of the invention is to-provide national electric codes,

meansto reduce the darkening eflect upon theinner side of fluorescent tubes, produced by the operation of the tube, and which is ordinarily more pronounced near the electrodes, thus increasing the light efilciency.

A further object of the invention is to trodes by positive ion bombardment, by gas conprovide means for heating indirectly the thermionic elecvection currents, and the reflection of-heat, prior electrode devices which are simple and compact Figure 3 is a rspective view of one electrode I device. I 7

Figure 4 is a transverse section taken on line. 4- -4 of Figure 2, 1 a

Figure 5 is a perspective view of the thermionic electrode,

Figure 6 is a central longitudinal section and which may be mounted within the tube of the lamp.

A further object of the invention is to provide means of the above-mentioned character having a thermostatic element which may be, arranged interiorly or exteriorly of the cold electrode.

A- further object of the invention is to provide a fluorescent lamp operating upon a low voltage invention,

same will have an increased efliciency over the present commercial tubes.

A further object of the invention is to provide means whereby the current and corresponding light output of the fluorescent tube can be varied during operation within greater limitswithout materially affecting the tube performance, than with the present commercial low voltage tube.

A further object of the invention is to provide a fluorescent lamp so constructed that the tube and electrodes can be processed by a special pumping schedule with the regular high. voltage bombarder transformer, thereby avoiding the complicated processing method heretofore employed. I r

A further objectof the invention is to provide In the accompanying drawings forming a part' of this application and in which like numeral are employed to designate like parts throughout the same;

Figure 1 is a side elevation of a fluorescent lamp embo'dying'the invention,

Figure 2 is a central vertical longitudinal section through the same, taken on line 2 2- of Figure 1,

through the same,

Figure 6a is a transverse section taken on line 6a6a of Figure 6,

Figure 7 is a diagrammatic view showing the circuit for the electrode devices,

. Figure 8 is a perspective view of an electrode device embodying a modification of the invention,

Figure 9 is a side elevation of an electrode device, embodying a further modification of the invention, parts being shown in section,

Figure 10 is a side elevation of a fluorescent lamp embodying a further modification of the ,Figure'll is a central vertical section through thesame, taken on line ll-ll of Figure'lo,

taken on line Attention being called first to Figures 1 to 7,

inclusive, the numeral l designates the tube of.

a fluorescent lamp; which tube may be formed of glass; and has its inner surface coated with fluorescent material II. This tube contains a gaseous atmosphere such as mercury and a carrier gas such as argon, neon, or a mixture of the same. The tube is evacuated prior to the introduction of the mercury and the carrier gas, as will be explained. v

Mounted within the opposite ends of the tube l0 are electrode devices 12, each of which comprises an auxiliary electrode l3, which is prefer ably cylindrical and is provided upon its inner side with a longitudinal opening or slot N. This cylindrical auxiliary electrode I3 is preferably arranged transversely of the tube and preferably extends diametrically of the same. The auxiliary electrode I3, is preferably formed of "SVEA metal, or nickel, while it 'may be formed of any other suitable metal.

Held within theopposite ends of each tubular auxiliary electrode 13 are insulating ends 'or disks l5, having openings to receive the terminals or plugs I 6 of a thermionic electrode ll. The terminals or plugs ii are preferably formed of nickel. The thermionic electrode ll includes a tube 18, receiving the plugs IS in its ends and spot welded to these plugsn The tube I8 is formed from a fine woven metallic mesh. The fine wire a mesh tube [8 is preferably formed of nickel, al-

though it may-be formed of tungsten, molybdenum; SVEA metal or pure iron'which is nickel plated or pure iron without the nickel plating.

' VEA" designates the trade name of the purest commercially produced iron made by a special process and freedto the highest extent from carbon and occluded gases. The tube It may have a mesh of from 50 to'400 mesh, but we prefer to form the tube of a mesh of from 100 to 300 mesh.

The wire from which the screen tube I8 is formed 60 has a diameter of from .0005" to .005" and we prefer using a wire having a diameter of .001" to .002". The inside diameter of the tube 18 may be from .008" to .060". The tube I0 is sprayed with an electron emission coating W. This coating may be of the usual composition containing barium carbonate and strontium carbonate with a suitable binders This coating is originally in the liquid form and is sprayed upon the wire mesh tube I8 and will become attached to the interior and exterior of the tube. After this I coating dries it is subjected to a heat-treatment whereby the carbonatesare converted into the oxides of barium and strontium. Since the mesh of the tube It is fine it is also necessary that the barium carbonate and strontium carbonate should be finely divided so that they will pass through at least a'200 mesh sieve. The advantage in using the tubular type electrode I1 is that the electron emission coating will adhere to the outer and inner surfaces of the tube in a superior manner than when such coating is applied to the .ordinary coil or filament electrode. While it is preferred to use the tube type thermionic electrode ll, yet it is to be understood that the ordinary coil or filament electrode may be substituted for the same, in which event the filament 'electrode would be spot welded to the plugs l8.

The numeral 19 designates a stiff U-shaped supporting element, formed of wire, the ends of which are spot welded to the terminalsor plugs l6. Rigidly attached to the supporting element is are still supporting wires 20, the ends of which are fused to and anchored within the head 2| of a stem 22. This stem has a part 23 which is fused, to the end of the tube III, as is well known.- The stem 22 is provided with a tube 24, the inner end of which is in communication with theinterior of the tube H), as shown at 2,5, and the outer end of this tube is closed by being pinched. The tube 24 is employed in evacuating the tube Ill. A stiff tact with the cold electrode 13. The free end of the thermostatic element I8 is disposed between the sleeve or electrode l3 and the base IQ of the supporting'ele'ment l9, and when the thermostatic element 28 is heated, it disengages the sleeve l3 and engages the base l9. Awire 29 is embedded in the head 2| and is electrically connected with the sleeve l3 through the medium of the wire 30. The wire 29 is also connected with a lead wire 3 l The wire 29 is only employed during the heating of the sleeve l3 for the processing of the sleeve I3, thermionic electrode I1, and the coating H of the tube III. A high bombarding current is supplied to the Wire ti and this heats the sleeve iii to a cherry red removing the occluded gases. At the same time, the barium and strontium carbonates of the coating of the tube this treatment will also remove the occluded gases from the coating ll. After this treatment the wires 3| are not used during the operation of,

the lamp. Prior to this heat treatment, the tube III has been evacuated, and after such heat treatment a small amount of mercury and a carrier gas, in a proper amount, is introduced into the tube lllthr'ough the tube 24 and the tube 24 is sealed.v

In Figure 7,'the numeral 32 designates a high leakage reactance transformer which has a high voltage reserve, whereby the failure of the tube to operate due to insuflicient voltage is eliminated. This transformer includes a secondary coil 33, the ends of which are connected with the lead wires 21. 3d designates the primary coil, connected in a circuit 35 having a source of alternating current I and a switch 31, and 34" is the laminated iron core.

-The operation or the apparatus is as follows: To operate the lamp, the switch 31 is closed. The thermostaticelements' 28 are now in electrical contact with the auxiliary electrodes or sleeves l3 and hence these auxiliary electrodes are connected with the opposite ends of the secondary coil, As soon as the switch 31 is closed, the

high potential being applied to the auxiliary electrodes It, the lamp is instantly lit up or struck and the auxiliary electrodes ii are heated. When this occurs, the thermionic electrodes H are sub- Jected to the heatingefiect of the positive ion bombardment and also from the hot gases surrounding th electrode l1 and also from the heat' reflected from the now heatedauxillary electrode of the secondary coil 33. As an illustration, when the opposite ends of the secondary coil 33were connected with the auxiliary electrodes 13, these auxiliary electrodes may be regarded as subjected to the action of 1000 volts, the instant that the switch 31 was closed, but this voltage will automatically drop to a somewhat lower voltage, de-

pending-upon the length and diameter of the tube, and this operation will take place while the auxiliary electrodes are still connected with the opposite ends of th secondary coil. Now when the auxiliary electrodes are disconnected from the secondary coil and the thermionic electrodes H are connected with the opposite ends of the secondary coil, which occurs after the thermionic electrodes ll have been heated, as described,

- the voltage will drop from 1000 volts to about 100 volts to 200 volts, as an example, depending upon the length and diameter of the tube. When this occurs the current will adjust itself to the'desired value. The secondary circuit is now made between the thermionic electrodes I! through the medium of the'vaporized mercury whereby ultra violet light is produced which acts upon the fiuorescent material I I, causing the lamp to glow, as is well known. The operation will continue until the switch 31 is opened after which the thermostatic elements 28 will cool and disengage the bases 19 and again engage the cold electrodes or sleeves l3.

When the thermionic electrodes H are operatin,g,,the auxiliary electrodes or sleeves l3 serve as guards for these'thermionic electrodes, thereonic electrode l1 mounted therein. The terminals l6 are spot welded to rigid support wires 4|, corresponding to the wires 20, and anchored in the head 2 l. A wire 42, corresponding to the wire 3|, is electrically connected with the sleeve l3.

- Disposed internally of the sleeve I3 is a bi-metal thermostatic element 43, extending longitudinally of the sleeve, and mounted upon a wire support 44, passing through the sleeve I3 and insulated therefrom. The wire support is connected with a wire 45, corresponding to the. wire 21. The thermostatic element 43 has a double ended contact 46, which engages the sleeve l3 whenthe thermostatic element 43 is cold, and breaks this engagement and engages a still contact wire 41, when the thermostatic element 43 is heated. The wire 41 is'spot welded to the terminals l6.

In Figures 10 to 15, we have shown a further modification oi the invention wherein a fluoarran ed innermost.

tively narrow so that the sleeve l3 will properly j serve as a guard for the thermionic electrode, but

the slot is sufficiently wide to permit of the proper electrical discharge. It is to be understood however that the width of the slot may be varied as may be found advantageous.

In Figure8, we have shown a modification of the invention. In this. figure the numeral 38 designates a bi-metal thermostatic element, extending longitudinally of the cold electrode or sleeve l3, and arranged between the sleeve [3 and the base- I9'. This thermostatic element 36 is attached to a still wire 39, connected with the wire 21. A double ended contact 40 is secured to the thermostatic element 38 and engages the sleeve i3 when the thermostatic element 38 is,

48, the inner surface of which is coated with a fluorescent material 49. Arranged within the opposite ends of the tube 46 are auxiliary electrodes or cups 50 preferably formed of SVEA metal or nickel, or SVEA metal nickel plated or of other suitable metal. These auxiliary electrodes extend longitudinally of the main tube 48 in spaced concentric relation thereto and their inner ends are The electrode or cup 50 is provided at its outer closed end with an insulating plug 5|, through which passes stiff supporting wires 52, embedded-in .the pinched end 53 of the tube 48. The wires 52 are rigidly held within the insulating plug 5| and serve to rigidly hold. the

cup 50 in place. A wire 54, corresponding to the and has a double ended contact 51 which engages I the cup 50 when the thermostaticelement 56 is cold but disengages the cup 50 arid engages a stiff contact wire 58, when the thermostatic element is heated. Thecontact wire 58 may be a continuation of one of the supportwires 52. The

is preferably identical with the tube H3. The

thermionic electrode 60 extends longitudinally of the cup 50 in spaced concentric relation thereto,

thermostatic device 40 two of which are applied to the tube H! in the manner shown in connection with the electrodes l2. Each device 40 includes the sleeve or cold electrode l3, having the thermiand elements 56 and 58 are arranged between it and the cup 50, as shown. While we preferto employ the tubular thermionic electrode 60, a filament thermionic electrode may be substituted for the electrode 60 and will be electrically mounted upon the plug 59.

, The operation of the variousforms of electrode devices described after the first form of the invention is so similar that a detailed explanation is deemed unnecessary. In connection with each modification after the first form'of the invention, the cold electrodes are first electrically connected with the opposite ends of the secondary coil, and when these cold electrodes are heated upon the closing of the circuit including the primary coil, the thermostatic elements then operate to disengage the cold electrodes and electrically connect with the thermionic electrodes, whereby these thermionic electrodes are connected ,with the opposite ends of the secondary coil.

In the operation of all forms of the fluorescent lamp of the present application, there is an instant when th thermostatic element disengages both the auxiliary electrode and the thermionic electrode, in the transition from the auxiliary electrode to the thermionic electrode. However, the lightdoes not go out. This is due to an electrical conducting path of ionized gas between the thermionic and auxiliary cathode elements of the electrode, also because of the sufliciently high secondary voltage of the transformer and a high instantaneous voltage induced by the' breaking of the auxiliary cathode circuit containing the transformer secondary reactance.

It is to be understood that the forms of the present invention herewith shown and described are to'be taken as preferred examples of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, what is claimed is:

1. In a gaseous discharge lamp, a container having a gaseous atmosphere, spaced tubular auxiliary electrodes within the container, a source of electrical potential, thermionic electrodes within the tubular auxiliary electrodes, said thermionic elecheated, said thermostatic elements being arranged within the tubular auxiliary electrodes.

2. In a gaseous discharge lamp, a container having a gaseous atmosphere, spaced tubular auxiliary electrodes within the container having contact parts, thermionic electrodes within the tubular auxiliary electrodes having contact parts,.

thermostatic elements arranged within the container and having connection with the opposite poles of a source of current and having parts disposed between the contact parts of the auxilelectrodes within the tube, thermionic electrodes within the tube and arranged in cooperative relation to the auxiliary electrodes to be heated thereby, and means for electrically connecting previously disconnected from the opposite poles of the source of current.

5. In a gaseous discharge lamp, a container having a gaseous atmosphere, spaced auxiliary electrodes within the container, thermionic electrodes within the container and arranged near the auxiliary electrodes to be heated thereby, means for connecting one auxiliary electrode with one pole of a source of current and the other auxiliary electrode with the opposite pole of the source of current whereby the auxiliary electrodes are heated solely by the electrical potential thereon, said means also serving to connect onethermionic electrode with one pole of the trically-connecting one auxiliary electrode with auxiliary electrode with the other pole of the' elect-ricalconnection with said poles of the source of current, said means including thermostatic iary electrodes and the contact parts of the thermionic electrodes to alternately engage with such parts, the thermostatic elements being heated by the action of the auxiliary electrodes,-

the auxiliary electrodes and the thermionic electrodes having electrical connection with the opposite poles of the source of current solely through the means of the thermostatic elements.

3. In a gaseous discharge lamp, a container having a gaseous atmosphere, spaced tubular auxiliary electrodes within the container,-tubular thermionic electrodes within the tubular auxil.

iary electrodes and insulated therefrom, and

means to alternately connect the tubular auxil-- iary electrodes and the thermionic electrodes with a source of potential, said means including thermostatic elements arranged within the container to be heated by th action ofthe tubular auxiliary electrodes, said thermionic electrodes being free from electrical connection with the one pole of a source of current and the other source of current, said means also serving to disconnect the .auxiliary electrodes from said poles of the source of current and to then connect one thermionic electrode with one pole of the source of current and the other thermionic electrode with the other pole of the source of current, the thermionic electrodes being previously free from elements arranged to be heated by the auxiliary electrodes.

7. In a gaseous discharge lamp, acontainer having a gaseous atmosphere, spaced auxiliary. electrodes arranged within the container,-spaced thermionic electrodes arranged within the container and disposed near the auxiliary electrodes to be heated by positive ion bombardment, gas

convection currents and the reflection of heat from the auxiliary electrodes when they are with said poles of thesource heated, means for connecting one auxiliary electrode with one pole of a source of current and the other auxiliary electrode with the opposite pole of the source of current, the auxiliary electrodes being heated solely by the potential applied thereto, said means also serving to connect one thermionic electrode with one pole. of.the source of current and the other thermionic elec-' trode with the other pole of the source of current and to disconnect the auxiliary electrodes from said poles of the source of current, said means including thermostatic elements arranged to be heated by the auxiliary electrodes. the thermionic electrodes being previously free from connection of current before the lamp is started.

8. In a gaseous discharge lamp. a container auxiliary electrodes within the container for connection with the opposite poles of a source of current, thermionic electrodes within the tubular electrodes and free from connection with the opposite poles of the source of current before the openings upon their inner sides, thermostatic ele -ments for connection with the opposite poles of lamp is started, a. thermostatic element con-.

nected with one pole of the source of current, a

opposite pole of the source of current, the thermostatic elements being heated by the auxiliary electrodes and when heated being adapted to have electrical connections electrodes.

9. In a gaseous discharge lamp, ,a container having a gaseous atmosphere, spaced auxiliary electrodes within the container for connection with the opposite poles of a source of current, thermostatic elements for connection with the opposite poles of the source of current and arranged adjacent to the auxiliary electrodes to be heated thereby, and thermionic electrodes arranged within the container and disposed in cooperativerelation with the auxiliary electrodes and being free from connection with the opposite poles of the source of current before the thermostatic elements are heated, the thermostatic elements when heated serving to connect the thermionic electrodes with the opposite poles of thesource of current; e

10. In a gaseous discharge lamp, 2. container having a gaseous atmosphere, spaced auxiliary electrodes arranged within the container for connection with the opposite poles of a source of current, thermostatic elements for connection with the opposite poles of; the source of current and in thermal contact-with the auxiliary electrodes to be heated by the auxiliary electrodes, and thermionic electrodes arranged within the container and disposed in cooperative relation to the auxiliary electrodes and being free from electrical connection with the opposite poles of the source of current before the thermostatic elements are heated, the thermostatic elements when heated servingv to connect the thermionic 11..I-n a gaseous discharge lamp, a container 1 having a gaseous atmosphere, spaced tubular auxiliary electrodes for connection with the opposite poles of a source of current andmounted within. the container and extending transversely thereof, the tubular auxiliary electrodes having with the thermionic second thermostatic element connected with the the source of current and arranged adjacent to the auxiliary electrodes to be heated thereby,--.v

thermionic electrodes mounted within the tubular auxiliary electrodes and insulated therefrom and free from con-nectionewith the opposite poles of the source of current before the thermostaticl elements are heated, the thermostatic elements when heated serving to connect the thermionic electrodes with the opposite poles of the source of current.

12. In a gaseous discharge lamp, a container having a gaseous atmosphere, spaced tubular.

auxiliary electrodes within the container for connection with the opposite pole'sof a source of current, said auxiliary electrodes having longitudinal openings, insulating disks held within mostatic elements for connection with the opposit poles of the source of current-and disposed adjacent to the auxiliary electrodes to be heated thereby, thermionic electrodes arranged within the tubular auxiliary electrodes and having parts -elements when heated serving to connect the electrodes with the opposite poles of the source 1 of current. g

thermionic electrodes with the opposite poles of the source of current.

13. In a gaseous discharge lamp, 9. container having a gaseous atmosphere, spaced tubular auxiliary electrodes arranged within the container for connection with the opposite poles of a source of current, said auxiliary electrodes having openings for the electrical discharge, thermostatic elements for connection with the opposite poles of the source of current and arranged adja cent to -the auxiliary electrodes to be heated thereby, thermionic. electrodes arranged within the tubular auxiliary electrodes and free from connection with the opposite poles of the source emission coating applied to the forami-nous tubular body portion, the thermostatic elements when heated serving to connect the thermionicelectrodes with the opposite poles of the source of current. a

PAUL manna-Korma.

, THOMAS M. CORTESE. 

